The invention relates particularly to a process for preparing either enantiomer of a compound of formula I:

wherein
X denotes O or CH2,
Y is NH or N-PG,
PG denotes a protective group
and
n denotes 0 or 1,
from the racemate of formula I or other mixtures of the enantiomers of formula I, with high enantiomeric excess (e.e.), by chiral resolution in the presence of a non-racemic, chiral acid.
Enantiomers of compounds of formula I are useful as drugs or building blocks for the synthesis of drugs, such as but not limited to glycosidase inhibitors.
For example, PCT/EP2015/069598 describes e.g. N-(5-{4-[(1S)-1-(2,3-dihydro-1-benzofuran-6-yl)ethyl]piperazin-1-yl}-1,3,4-thiadiazol-2-yl)acetamide and N-(2-{4-[(1S)-1-(2H-1,3-benzodioxol-5-yl)ethyl]piperazin-1-yl}pyrimidin-5-yl)acetamide as active glycosidase inhibitors having high inhibitory activities.
There is a need to identify the conditions and solvent systems in combination with chiral acids that can be employed reliably in processes that provide efficient resolution of the racemate of formula I.